Long and winding wires

A new standard improves and clarifies the continuity tests for winding wires, making them more reliable and reproducible for on and offline measurement

By Catherine Bischofberger

Millions of kilometres of winding wires are produced every day – enough to go around the earth at least ten times! IEC Standards make sure they are used safely in millions of devices. They also pave the way for future developments involving the use of nano materials and electric vehicles (EVs).

Winding wires can be densely packed in small areas ( Photo: Shutterstock)

Winding wires are far from being on everybody’s radar and yet perhaps they should be. They are in millions of electric and electronic devices we use every day and are a key component which enables these items to perform properly, safely and in an energy-efficient manner.

“Winding wires are in anything that needs an electric motor, a generator or a transformer, basically. There are many different applications in the white goods industry: winding wires are in most of the consumer electronic devices which make our lives easier at home. Whether utilized as conductors or primary insulators, they are also essential parts of the different motors used in cars, for instance. They are employed in the windscreen wiper motors as well as in the valves and ventilation devices used around the combustion engines, to name but a few. They are also widely deployed in industrial applications for automation or in wind turbines”, confirms Andreas Levermann, one of the experts of IEC Technical Committee 55: Winding wires.

In electric motors, these key components transform electrical energy into mechanical energy by creating electromagnetic fields. Most of the wires are made of very pure copper, a highly conductive material, which can be densely packed into small areas. “If the requirements are for lighter wires, aluminium can sometimes be used but it is less conductive than copper and is therefore not suitable for high efficiency applications”, Levermann points out.

New standard for continuity specifications

Winding wires are so ubiquitous that manufacturers produce millions of kms of wire a day. “I would say that each day, enough winding wire is produced to go around the earth at least ten times”, Levermann remarks. Yet, the technology to produce these wires is very complex. “So many different properties are required: thermal, electrical, dimensional, chemical, insulating… The IEC 60317 and IEC 60851 series, which together comprise more than one hundred standards, deal with those aspects”, Levermann explains.

Levermann heads the working group which developed the new edition of IEC 60851-5, that now exists in a consolidated version, including the amendments made in 2008 and the very recent ones added in 2019. “The important aspect we wanted to specify in the new edition is continuity measurement. When you produce millions of kms of winding wire, it is impossible to avoid insulation weaknesses. IEC 60851-5 specifies reliable test methods and a low number of defects for a given length of wire. We worked hard to make this standard as international as possible – it is a compromise that makes it suitable for a wide number of countries”, he says. IEC TC 55 members reflect this striving for compromise: all continents are represented, with participating National Committees from China, France, Germany, India, Iran, Italy, Japan, Russia and the US as well as many observing countries, including Australia, Brazil and South Africa.

What’s in the future for wires?

Demand from electric and hybrid car manufacturers is growing rapidly, leading to new levels of quality requirements for winding wires such a resistance to pulse endurance testing. The TC is studying a project which may lead to new standards in that area.

New insulating materials are also being developed which might have an impact on IEC TC 55 Standards. “We liaise with a number of technical committees and one of them is IEC TC 113: Nanotechnology for electrotechnical products and systems. New nano materials can be included in the enamels, which are used as insulating layers in the wires. This can lead to enhanced or even new properties, such as lower coefficients of friction or higher corona resistance”, Levermann informs.

Cutting-edge, energy efficient, safe…Winding wires will continue to be essential in years to come and will remain as unobtrusive as they have always been – thanks to IEC Standards.

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Winding wires can be densely packed in small areas ( Photo: Shutterstock)

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